Table 29-1 gives an overview over the
commands available in pgtcl. These
commands are described further on subsequent pages.

Table 29-1. pgtcl Commands

Command

Description

pg_connect

open a connection to the server

pg_disconnect

close a connection to the server

pg_conndefaults

get connection options and their defaults

pg_exec

send a command to the server

pg_result

get information about a command result

pg_select

loop over the result of a query

pg_execute

send a query and optionally loop over the results

pg_listen

set or change a callback for asynchronous notification messages

pg_on_connection_loss

set or change a callback for unexpected connection loss

pg_lo_creat

create a large object

pg_lo_open

open a large object

pg_lo_close

close a large object

pg_lo_read

read from a large object

pg_lo_write

write to a large object

pg_lo_lseek

seek to a position in a large object

pg_lo_tell

return the current seek position of a large object

pg_lo_unlink

delete a large object

pg_lo_import

import a large object from a file

pg_lo_export

export a large object to a file

The pg_lo_* commands are interfaces to the
large object features of
PostgreSQL. The functions are designed to mimic the analogous file
system functions in the standard Unix file system interface. The
pg_lo_* commands should be used within a
BEGIN/COMMIT transaction
block because the descriptor returned by
pg_lo_open is only valid for the current
transaction. pg_lo_import and
pg_lo_exportmust be used
in a BEGIN/COMMIT transaction
block.